This invention is in the field of etching and more particularly those devices which are used to etch glass with abrasive particulate material. A variety of devices have been used to etch glass. For example, vibratory devices have been used to etch letters and other symbols into a variety of surfaces including metal surfaces as well as glass. Vibratory etching techniques typically require each etched symbol to be manually traced. On the other hand, it is possible to etch an entire symbol upon a surface by using a mask outlining the symbol and by then blasting abrasive particulate material against the surface. Relatively large compressors are required to force the abrasive particulate material with sufficient force to cause the desired result. In the U.S. Pat. No. 3,267,621 issued to W. F. Meyers et al., a single grit blast nozzle is disclosed along with a resist mask screened on the tumbler to be etched with a particular design.
The grit blast technique of etching a glass tumbler is particularly disadvantageous in that the compressor must be large to force the grit with sufficient speed against the tumbler. As a result, the glass will frequently break, especially in thin-walled vessels as a result of the grit impinging the thin wall with great force. In addition, the large compressors not only consume a large amount of electrical current, but in addition frequently break down necessitating expensive repairs. There is a particular need for a device for etching designs, such as a person's initials, in a variety of thin-walled glass vessels. Disclosed herein is such a device which is sufficiently small to be easily carried into a shopping center mall wherein the etching service business may be accomplished on a relatively temporary or movable basis. The device disclosed herein uses an impellor to throw the grit against the surface being etched in lieu of blasting the grit and as a result, the device may be operated by conventionally available sources of electrical energy without requiring a large amount of electrical current for operation. The device further enables etching of the thin-walled glass vessels, such as wine glasses, without any danger of breakage from the etching process.
It is known to etch by means of throwing the grit in lieu of the traditional blast method. For example, U.S. Pat. No. 3,675,373 issued to David T. Putnam discloses a wheel which discharges by centrifugal force abrasive particles. Further, it is known that spark plugs may be cleaned with grit-throwing devices such as are disclosed in the U.S. Pat. Nos. 3,704,552 issued to Bud K. Beaver et al. and 3,868,790; 4,028,851; and 4,062,155 all issued to Roy A. Fricke.
Another need not satisfied by the heretofore known devices is the ability to etch vessels having a variety of different-sized radial surfaces without necessitating a special adaptor to conform to the surface being etched. The device disclosed herein will etch a symbol on surfaces of a wide radial range without requiring a special mask adaptor.